The invention relates to a machine for the formation of ornamental chains, from precious metals, and to those employed in the manufacture of costume jewelry; more specifically chains of the type known as rolo in the Italian trade.
The prior art in jewelry manufacture embraces a number of machines capable of crafting a wire from which chains are ultimately produced.
One such machine winds wire around a link former into a helicoid that is cut into discrete lengths the shape of which resembles an open link; the open links are then closed by joining up the ends, and connected one with the next in sequence.
Another type of machine, which is used in the manufacture of rolo chain, first cuts the wire into discrete lengths, then forms the links and connects them one with the next. Such a machine consists substantially of a link former, a pincer positioned beneath the former, and a die above the link former wherein the pincer and die are aligned vertically one with the other, at opposite sides of the link former, and with the link former itself.
The wire, indexed between the former (above) and the open pincer (below), is held fast by a clamp mechanism during operation of a cutter. The cutter is positioned alongside the clamp mechanism, and severs the wire into discrete lengths striking in the opposite direction to the approach of the pincer while the wire is held in position by direct contact with the pincer and the former on one side of the cut, as well as by a retainer located alongside the pincer on the other. The pincer rises and draws together, wrapping the length of wire around the bottom of the former, whereupon the die descends and bends the ends of the length of wire together over the top of the former, thus creating the link. The pincer is distanced by traversing parallel with its own axis, then turned through 90.degree. and lowered as the wire is indexed so as to pass through the previously former link, following which the pincer opens, allowing the former link to drop onto the wire and hang, before turning through 90.degree. once again, this time in the opposite direction, in readiness for formation of a fresh link.
The chain, growing link by link, descends through an axial bore in the pincer, and is taken up by a station downstream which solders together the ends of each link.
A machine thus embodied is of proven effectiveness as regards formation of a chain in a faultless manner, but exhibits numerous attendant drawbacks of a nature that compromise practical expediency.
First, the chain must be taken up afresh in order to solder together the ends of each link, with the result that considerable time is wasted, and the finished join not always as accurate as requirements dictate.
Second, the machine is particularly lacking in flexibility since, while it is true that machines of the type permit forming of chain links, the actual shapes obtainable exhibit but little variety from one link to another.
Accordingly, the object of the invention disclosed herein is that of overcoming such drawbacks.